Inductive power has been a main source to supply biomedical implants, which require a reliable and efficient DC powering scheme. Modern implants rely on mixed-mode designs and inevitably require multi-voltages to optimize the system power. Furthermore, implants are usually operated under physics and regulatory service regulation on tissue absorption (e.g. SAR and field strength), which implies the constraints of frequency, power and size. An example of a conventional solution uses external diodes to produce multi-voltages at the penalty of large foot print, e.g. [1] and [2]. In contrast, integrated solutions have been proposed. Examples include a low-voltage (LV) AC-DC converter [3], rectifier [4], as well as the switched-capacitor converter for multi-voltages using a high frequency clock [5], which is not applicable for most size-limited biomedical implants. A high-voltage (HV) rectifier using HV CMOS is also reported [6] with a deficiency of substrate leakage current and latch-ups.
To generate multi-voltages at a high efficiency for the biomedical implants, such as, but not limited to, retinal prostheses, the present invention advances the art by providing an integrated timing control based rectifier using a multi-well structured CMOS process.